The problem of such aerodynamic surface icing is well known in the aviation industry. The aerodynamic profile of such a surface can become modified by ice forming thereon, as a result of the flying aerodynamic surface encountering droplets of super-cooled water contained in the atmosphere.
This problem is often treated by fitting the aerodynamic surface with a heater structure.
To do this, e.g. in a rotorcraft, a plurality of heater resistances are embedded in the blades of the main rotor and of the tail rotor. In order to reduce significantly the amount of electricity consumed, the various resistances are powered cyclically, and not simultaneously.
Document EP 0 014 334 discloses a device of that type which delivers electricity sequentially and cyclically to a plurality of anti-icing/de-icing modules. Each module is physically and electrically powered independently of the others. Consequently, the connections between the modules and the power switch unit comprise a large number of cables, which is extremely penalizing in terms of weight.
Concerning electricity consumption, each module is powered cyclically for a determined length of time in order to ensure that the temperature at the skin of the blade is sufficiently high. Nevertheless, because of variations in the flow of air over the aerodynamic surface, because of the possible presence of water or ice, and because of the absence of the temperature of the heater element being servo-controlled, it can happen that the blade is heated excessively, which can lead in the end to the skin or the internal structure of the blade being destroyed.